1. Field of the Invention
The present invention relates to mechanical change-gear transmissions of both the simple and compound type wherein the countershafts constantly driven by the input shaft are compounded and comprise a first portion and a second portion, the second portion telescopically surrounding the first portion, mounted for relative rotation therebetween and in constant driving relation therewith by means of an idler gear.
2. Description of the Prior Art
Mechanical change-gear transmissions of both the single and multiple identical countershaft type are well known in the prior art, as may be seen by reference to U.S. Pat. Nos. 3,105,395; 3,648,546; 4,754,665; 4,876,924 and 4,974,468, the disclosures of which are incorporated herein by reference.
The use of mainsection and auxiliary section countershafts in a compound transmission wherein one of the countershafts is a sleeve supported by the other countershaft is known in the prior art, as may be seen by reference to U.S. Pat. No. 5,390,561, the disclosure of which is incorporated herein by reference.
The use of compounded countershafts to provide an extended ratio range without unduly increasing the center distances in a simple transmission wherein each countershaft portion comprises a separate shaft, each requiring bearing support in a transmission end or intermediate wall at each end thereof, is known in the prior art, as may be seen by reference to U.S. Pat. No. 4,152,949, the disclosure of which is incorporated herein by reference.